I NEED TO KNOW IF I NEED TO REPLACE THE RADIATOR WITH A BIGGER ONE OR NOTON MY"02" 4.8 SIERRA,AND WHAT KIND OF HARNESS I NEED TO GET,AND HOW MUCH HP GAIN I SHOULD EXPECT IF ANY?

 

I wouldnt switch your rad if you got the small one (witch you should with the 4.8) just use the e-fans from a LS1 Firebird or Camero. You can get a harness from http://www.nelsonperformance.com/ Im not sure but you may need a tune. Or you could run a switch or just have them on all the time. Not a big gain for hp but it dose get better with added mods. Also you could go with this--- http://cgi.ebay.com/ebaymotors/ws/eB...:IT&ih=014
You can look around on ebay and find others.

 

10-4 your 4.8 should have the 28in radiator to do the 05',06' fans on your 02' (wich great idea weather you go that route or aftermarket getting rid of that fan clutch setup is a smart move) you need to get the 34in radiator from the 05-06 i think it cameina couple other years to. use www.nelsonperformance.com they make afactory looking harness for this very swap. i've got one myself but have yet to find the fans yet,the factory ones that is. i have heard that that you will need a tune, if not the fans stay on when the key is on no biggie though...

 

MY06TRISH
I have a 2004 gmc 5.3 and changed fans.go to GM Parts Direct.com
1-89023368-motors-found on e-bay-$73.50 for two-what a steal.
2-890223365-shroud-$134.26
3-89023366-blade-right-$47.37
4-89024933-blade-left-$44.91
5-www. Radiator.com $178.oo-34x17x1
6-Nelson fan harness,$89.00,enable fans,$25.00,core for fan activation $55.00-total-$180.0
yes a lot of money,my 04 looks like a 05 stock set up.look at JB 2004 ride and you see why I did itmore h/p